Electrical switches



Feb. 9, 1960 s. T. DEAKIN 2,924,676

ELECTRICAL SWITCHES Filed 001;. 11. 1957 ST.-.NLEY THOMAS DEAKIN Inventor A Attorneys United States Patent 2,924,676 ELECTRICAL SWITCHES Application October 11, 1957, Serial No. 689,558

Claims priority, application Great Britain October 17, 1956 3 Claims. (Cl. 200-15) This invention relates to electrical switches wherein a movable switching member is adapted to selectively connect with fixed contacts.

Such contacts often comprise a pair of resilient prongs so arranged that when a movable switching member is pushed between them they will press against the member with good electrical connection while at the same time permitting ready disengagement of the member.

It is an object of the present invention to provide a switch having fixed contacts capable of simple manufacture and having a high degree of resilience.

Accordingly the present invention provides an electrical switch comprising a plurality of fixed contacts and a movable switching member adapted to selectively connect with one or more of said contacts, said contacts each being formed of sheet metal and comprising a pair of prongs and a tag portion extending from the root ends of the prongs, the prongs being twisted in the same angular direction about parallel longitudinal axes and the laterally extending bends formed by the twisting operations each having varying radii of curvature, the radius of curvature of each prong being greatest at the inner edge i.e. adjacent the line of separation of the prongs and decreasing progressively to the outer edge so that the free ends of the prongs overlie each other and are adapted to resiliently press against opposite sides of the switching member when inserted between them.

In one embodiment of the invention the switch may be arranged for rotary action of a movably switching member in which case the switch comprises a plurality of contacts distributed round the periphery of a circle and extending radially thereof with their free ends facing inwardly of the circle and a rotatable switching member pivoted about the centre of said circle and adapted, on being rotated, to connect with successive contacts. Preferably the free ends of the contacts extend sideways circumferentially of the circle and are swaged or bent at their side edges to assist entry of the rotatable member.

In order that the invention may be more fully understood, reference will now be made to the accompanying drawing in which Fig. 1 shows one embodiment of the invention and Fig. 2 shows a rotary switch embodying an alternative form of the invention.

Referring to Fig. 1 there is shown therein a single pole double throw switch comprising an insulating body 1 carrying a movable switching member 2 having two alternative positions as shown by full lines 3 and dotted lines 4. Switching member 2 is controlled by a toggle mechanism well known in the art and no further description thereof is deemed necessary. Mounted on the insulating body 1 are two fixed contacts 5 and 6. These contacts are each formed of sheet metal and comprise a pair of prongs 7 and 8 located in the same plane and a tag portion 9 extending from the root end of the prongs at right angles thereto. This tag portion at its "end 10 is bent at right angles to form a lug which is attached to the insulating base member 1. The prongs are twisted about parallel axes extending longitudinally of the prongs so that the lateral bends produced thereby each have a varying radius of curvature the radius of curvature being greatest at the inner edge, i.e. adjacent the line of separation of the prongs. The free ends of the prongs overlie each other and are adapted to resiliently press against opposite sides of the switching member 1 when it is inserted between them. The manufacture of such contacts is described in my US. Patent No. 2,779,011.

Referring now to Fig. 2 there is shown therein a rotary switch comprising a plurality of fixed contacts 11 having their tag portions secured to an insulating block 13 and distributed round the periphery of a circle and extending radially thereof with their free ends 12 facing inwardly of the circle. The free ends of the prongs are extended circumferentially of the circle and are swaged or bent at their sides 14 to permit entry of a rotatable switching member 15 pivoted about the centre of said circle.

What I claim is:

1. An electrical switch comprising an insulating body, a set of fixed contacts mounted on said body portion and arranged in the same place and a rotatable switch member mounted on a support integral with or secured to said insulating body and adapted to selectively connect with each of said contacts, said contacts each being formed of sheet metal and comprising a tag portion secured to said body and a pair of prongs extending longitudinally from said tag, said prongs being rotated in the same angular direction about their individual longitudinal axes substantially into parallel planes, the root ends of said prongs having opposite bends produced by the rotation thereof, said bends extending about axes of curvature extending laterally and each bend having a varying radius of curvature, the radius of curvature of each bend being greatest along the longitudinal centre line of the contact member and decreasing progressively to the outside thereof.

2. An electrical switch comprising an insulating body, a plurality of fixed contacts mounted on said body, and distributed around a pitch circle and extending radially thereof, said contacts comprising tag portions extending outwardly of the circle and secured to the insulating body and a pair of prongs extending inwardly of the circle, said prongs being rotated in the same angular direction about their individual longitudinal axes into planes which are parallel to each other, the root ends of said prongs having opposite bends produced by the rotation thereof, said bends extending laterally and each bend having a varying radius of curvature, the radius of curvature of each bend being greatest along the longitudinal centre line of the Contact member and decreasing progressively to the outside thereof, and a rotatable arm pivoted about the centre of said circle and arranged on being rotated to lie between the free ends of successive contacts.

3. An electrical switch comprising an insulating body structure, a plurality of fixed contacts mounted on said body structure and distributed around the periphery of a circle and extending radially thereof, and comprising a tag portion extending outwardly of the circle and a pair of prongs extending inwardly of the circle, said prongs being rotated in the same angular direction about their individual longitudinal axes into planes which are parallel to each other, the root ends of said prongs having opposite bends produced by the rotation thereof, said bends extending about axes of curvature extending laterally and each bend having a varying radius of curvature, of said circle and arranged on being rotated to lie b cthe radius of curvature of each bend being greatest tween the free ends of successive contacts. along the longitudinal centre line of the contact mem- References Cited in the file of this patent her and decreasing progressively to the outside thereof, free ends to said prongs extending sideways circumfer- 6 UNITED STATES PATENTS entially of the circle, outwardly chamfered ends to said 2,186,949 Allison Jan. 16, 1940 free ends and a rotatable arm pivoted about the centre 2,779,011 Deakin Jan. 22, 1957 

